Supersaturated? - Laying concrete slab over boggy ground

[whitefox]

This is my first post so be gentle!

I have begun a DIY project to lay a driveway to the side of my house. Because of the general instability of the ground (built over a steep-ish hillside) I have opted for a concrete slab with block paving over.

The ground has now been leveled & compacted ready for the concrete but I'm a little unsure about something: Where the ramp comes down to meet the road surface the ground behaves as if there is a massive balloon or bubble just below the surface; if my memory of the little geology I learned at school is correct then I think this is called "Super-Saturation".

This 'Bubble' is on the uphill side of the house's underpinning so it's unlikely to go anywhere and I can't see digging it out as an option. Can anyone advise me what to do about it?

Thank you

Whitefox

[Tony McC]

Without seeing the site, the best I can advise is that you dig down into the soft spot, remove as much as poss, cover the excavation with a geotextile, backfill with Type 1 in layers not exceeding 200mm deep, and then place your concrete on a damp proof membrane.